I want to use it in an aroma lamp. How many drops should I use and how long will the scent last?

For an aroma lamp or ultrasonic diffuser, start with 3–5 drops of grapefruit essential oil in the water reservoir. This creates a fresh, bright citrus aroma that can help a space feel cleaner and less heavy. The scent typically disperses into the room within 15–30 minutes and may last for 1–2 hours of continuous diffusion, depending on the room size and air circulation. Grapefruit oil's scent is often described as uplifting and refreshing, making it a good choice for mornings or when you want to create a lighter atmosphere without the intensity of floral or resinous oils.

You can blend it with other citrus oils like sweet orange or lemon for a more complex aroma, or with a small amount of peppermint or rosemary for an energising effect. Remember to clean your diffuser regularly with water and a mild soap to prevent oil residue buildup, which can affect performance and scent purity. Diffusing is primarily for aromatic enjoyment and creating a pleasant sensory environment.